1. Field of the Invention
The present invention relates to a camera that has a function to photograph a targeted object from a fixed point under a fixed condition.
2. Description of the Related Art
Fixed-point photography is known. In fixed-point photography, photographing is carried out from a fixed point at a fixed time interval or under a fixed focal length. For example, fixed-point photography is carried out when photographing a certain landscape during different seasons by photographing it at several different times. By fixing a camera in one position, fixed-point photography can be easily carried out. Accordingly, a camera used in fixed-point photography, such as a surveillance camera, is generally fixed at a certain location. For an amateur photographer who is practicing fixed-point photography as a hobby, it would be incommodious for the hobbyist to fix the position of the camera. In such a case, a user should set up a camera at the same location where the camera was used on a previous photographing operation and make sure that all photographing conditions, such as angle of view (equivalent to focal length) and photographing direction, coincide with the photographing conditions from the previous photographing operation. But it is difficult to measure and record the exact location where the camera was set up on a previous photographing operation. And even if a user was successful at measuring and recording the location, it would be very difficult to determine the exact position of the camera on the previous photographing operation, and then accurately reposition camera exactly as it was before. Neither is it easy to set the angle of view and photographing direction by referring to a photograph taken during a previous photographing operation. In Japanese Unexamined Patent Publication No. 2004-32286, a camera apparatus having a GPS receiver and an azimuth sensor, which measure the location of the camera apparatus and the photographing azimuth, respectively, and having a function to generate location and azimuth data and add them to the image data generated during the photographing operation is described. Using such a camera apparatus, fixed-point photography can be carried out by setting up the camera at the exact same location and orientation on the basis of the recorded location and direction data.
However, the camera apparatus provides only location and direction data. For fixed-point photography, a user should also measure the present location and photographing direction of a camera, and then position the camera so that the present location and photographing direction coincide with the recorded location and photographing direction, respectively. But setting up a camera for fixed-point photographing under these conditions is both tedious and time-consuming.